The Bellevue-based Valve Corporation has leased 225,000 square feet with the Kemper Development Company in the new office tower at Lincoln Square’s expansion.

The total expansion of Lincoln Square will entail 1.5 million square feet, and 710,000 square feet in the office tower. Valve will take up nearly a third of that tower office space, leasing floors 11 through 19.

Valve is a software developer that has created the award-winning Half-Life, Portal and Team Fortress video game series. It also developed the Steam client to host and play games.

The company was founded in Kirkland in 1996 but moved to Bellevue in 2003 and leased space in another Kemper Development Company building in 2010.

The move to Lincoln Square will effectively double Valve’s office space by adding 100,000 square feet for the more than 330 employees.

Valve is scheduled to move into the Lincoln Square tower in late spring of 2017.